This invention relates to a manufacturing method to obtain the structure of a standard signal generating apparatus including a plurality of signal generators comprising an oscillator having a non-adjusting thin plate vibrator fabricated with etching and a variable dividing circuit, and to fabricate a plurality of the signal generators at the same time, and more particularly to the standard signal generating apparatus for a time standard of the watch fabricated by the method according to the present invention.
Conventionally, as shown in FIG. 1 a watch type of standard signal generating apparatus is arranged with many signal generating units on one transparent substrate 1 and the common connecting leads 3 of each of the signal generating units and the elongated leads 4 of each of the signal generating units serves as the distributed lead electrodes on the surface of the substrate.
Further, FIG. 2 shows a sectional view of the signal generating unit and shows the thin plate quartz crystal vibrator 5, the oscillator making the quartz crystal vibrator oscillate and the integrated circuit element 6 having another function.
The vibrator 5 and integrated circuit element 6 are encapsulated to maintain a vacuum and inert gas-atmospher with the cover 7 made of a ceramic material or the like and the cover 7 is encapsulated to maintain airtightness with adhesive 8. In such conventional structure, both of the cover and the adhesive must be insulating material because the cover is subject to the condition that the respective connecting leads are electrically insulating each other.
Accordingly, the defects are as follows;
(1) In the sectional view of the cover portion including the connecting lead and the elongated lead (pattern of electrodes) illustrating the transparent substrate 1, the connecting lead 3 or the elongated lead 4, the low melting point glass 8 and the cover 7 of the ceramic material, the boundary of the respective layers is insufficiently airtight and reliable. Especially, the boundary of the conductive material is insufficient to maintain airtightness and reliability. PA1 (2) The cover of the ceramic material needs to have considerable thickness in order to secure the airtightness so that the miniaturization of the cover is difficult. PA1 (3) There are the high molecular weight materials such as the plastic and the epoxy resins. However, these insulating materials can not secure the vacuum. PA1 (4) The processing temperature at which the cover is fixed and is sealed to the substrate with low melting point glass is 500.degree. C. This temperature destroys the operating function of the vibrator and the integrated circuit element so that the productivity of the signal generating unit is low. PA1 (5) The cover which has the predetermined height with the calcined manufacture of the ceramic material is high in cost.